The CD player provided with the stopper which is configured to stop the CD when the CD is conveyed by the conveying roller to the mountable position on the turntable is well-known. Playback substrates are freely movably supported in a frame of the CD player, so that the vibration resistance can be improved. A CD player disclosed in the Japanese unexamined patent application publication No. 2005-302217 (hereinafter referred to as patent document 1) comprises the following components: a conveying roller configured to convey a CD from a CD insert to a channel on a playback substrate, a test rod configured to determine the outside diameter of the CD, and a stopper 8a configured to stop a minor-diameter CD conveyed by the conveying roller at a mountable position of a turntable. However, when a major-diameter (12 cm) CD is conveyed by the conveying roller, a front end of the stopper illustrated in the patent document 1 will rotate towards the insert, and the major-diameter CD will be away from the stopper. When a minor-diameter (8 cm) CD is conveyed by the conveying roller, the stopper holds still.
As described above, if the stopper 8a does not move when the minor-diameter CD is in the playback state on the playback substrate, when the playback substrate moves in a frame, the periphery of the minor-diameter CD will make contact with the stopper, and hence the playback of the minor-diameter CD will be hindered. Therefore, a stopper release mechanism configured to enable the stopper to be away from the CD is to be arranged. In this way, even if the playback substrate moves in the frame, the abutting connection between the stopper and the CD can be avoided.
In a CD playback player disclosed in the Japanese unexamined patent application publication No. 2008-226335 (hereinafter referred to as patent document 2), a playback substrate 15 is freely movably supported on a lower substrate 11 via a retainer plate 12. In addition, an upper substrate is provided with two test rods 45 and 46 configured to determine the outside diameter of a CD, two stopping members 97 and 98 driven to rotate by the CD, two moving members 142 and 143 configured to enable the stopper to be away from the CD, two synchronizing gears 144 and 145, and a cam plate 181 configured to drive one moving member 143 to move when the CD is kept in the playback state on the playback substrate 15. Moreover, when the CD is kept in the playback state on the playback substrate, the two moving members are driven to move towards mutually separating directions by the movement of the cam plate, and enable the stopping members to be away from the periphery of a major-diameter CD and a minor-diameter CD.
The stopper release mechanism of the CD player disclosed in the patent document 2 has a complex structure and includes: the two moving members 142 and 143 configured to enable the two stopping members 97 and 98 to be away from the CD in order to enable the stopping members to be away from the major-diameter CD and the minor-diameter CD, the two synchronizing gears 144 and 145 configured to enable the moving members to move synchronously, and the cam plate 181 configured to drive one moving member 143 to move when the CD is kept in the playback state on the playback substrate 15. Moreover, as the two stopping members 97 and 98 are driven to rotate by the major-diameter CD, the conveying roller is required to have a conveying force capable of overcoming the resistance.